What are the fundamental components of Domain-Driven Design?

Domain-Driven Design (DDD) is a software development approach that focuses on modeling software to match the business domain it serves. The fundamental components of DDD include:

1. Domain

The domain refers to the specific business context or problem space that the software is intended to address. It encompasses the real-world concepts, rules, and processes that the software models and supports[1][2][4].

2. Domain Model

The domain model is a conceptual representation of the business domain. It captures the essential elements, entities, and relationships within the domain. This model serves as the blueprint for the software's design and is developed in close collaboration with domain experts[1][2][4].

3. Ubiquitous Language

A ubiquitous language is a shared language used consistently by both software developers and business stakeholders throughout the software development process. This common language ensures clear communication and a unified understanding of the business domain, reducing the likelihood of misunderstandings or misinterpretations[1][2][3].

4. Bounded Contexts

Bounded contexts define logical boundaries within the system where a particular domain model applies. Each bounded context encapsulates its own ubiquitous language and domain model, allowing different parts of the system to evolve independently while maintaining consistency within each context[1][2][3].

5. Entities

Entities are objects within the domain that have a unique identity that persists over time, despite changes in their state or attributes. For example, a customer in a customer management system is an entity with a persistent identity[1][2][3].

6. Value Objects

Value objects are immutable objects that describe certain aspects of the domain but do not have a unique identity. They are defined by their attributes rather than by an identity. For example, an address can be a value object[2][3][4].

7. Aggregates and Aggregate Roots

Aggregates are clusters of related objects that are treated as a single unit for data changes and consistency enforcement. Each aggregate has an aggregate root, which is the entry point for accessing and modifying the aggregate's internal state[2][3][4].

8. Domain Events

Domain events capture and communicate significant changes or occurrences within the domain. These events are published and can be consumed by other parts of the system, enabling loose coupling and maintaining consistency between different bounded contexts[2][3][4].

9. Repositories

Repositories are mechanisms for encapsulating storage, retrieval, and search behavior, which emulates a collection of objects. They provid...